>On the other side, does a SOAP client have a guarantee that a
>message with a 500 status code is equivalent to a SOAP Fault?
>If not, SOAP clients will need to parse the response for the
>actual fault no matter what they do. It seems that using 500
>is another instance of a 'hint' in the protocol binding that
>is searching for a purpose; what concrete use cases are there
>for the hint?
No, the HTTP processing model is not a hint - it is a mechanism for
figuring out in an automatable manner what happened to a specific HTTP
request with a specific set of HTTP semantics so that caches and other
downstream clients can figure out what to do.
HTTP clients may look around in the message to find information related
to the status code. Typical examples are a Location header field etc.
However, in the case of SOAP, the information is carried in a SOAP
envelope which HTTP doesn't know anything about.
I would note that SOAP is not just a form submission - it is in fact its
own protocol with fault semantics etc. so I don't think the analogy to
form submission is good.
Henrik